Gas generating apparatus



Aug. 22, JOHNSON GAS GENERATING APPARATUS Original Filed June 19, 1929 3she t -sheet l INVENTOR ALFRED -JOHN6ON BY 2 ATTORNEY Aug. 22, 1933.JOHNSON 1,923,541

GAS GENERAT ING- APPARATUS Original Filed June 19. 1929 3 Sheets-Sheet 2INVENTOR ALFRED JOHNSON ATTORNEY Aug. 22, 1933. A, JOHNSON GASGENERATING APPARATUS Original Filed June 19. 1929 3 sh t -s t 5 I200I400 MEAN MiTAL TEMPERATURE-W 0 0 0 m m k 4 7 MEAN THICKNESS 0F FOEL-INCHES I INVENTOR ALFRED JOHNSON ATTORNEY Lil Patented Aug. 22, 1933ii-siren stares GAS GENERATING APPARATUS Alfred Johnson, West Island, N.Y.,

assignor New Brighton, Staten to Combustion Utilities Corporation, NewYork, N. Y., a 001'- poration of Maine Original applioationJ-lunc 19,1929, SerialNo.

Divided and this application August 22, 1931. Serial No. 558,663

19 Claims.

The present invention relates-to processes and apparatus for thedistillation of carbonaceous fuels, and more especially it concerns aprocess and apparatus for the concurrent carbonization in place of highvolatile bituminous fuels such as coal and the gasiflcation of theresidual coke in a semi-continuous succession of operations in anintegral unit having a carbonization zone of limited annular crosssection positioned in the upper end of a gas generator casing directlyabove the fuel bed of the latter.

This application is a division of my copending United States applicationSerial No. 372,112, for Process for distillation of carbonaceous fuelsfiled June 19, 1929.

The advantages to be gained by the carbonization of fuels in thin layersare now ,well known. It has been determined that the rate of fuelcarbonization by external heating-particular1y when employingtemperatures within the low temperature carbonization range,issubstantially inversely proportional to the square of the thickness ofthe fuel layer being carbonized;--for example a fuel layer 3 inthickness, when heated to a given temperature from each of the sides ofthe acid layer, will carbonize in one-quarter the time required undersimilar conditions for carbonizing a 6 layer of fuel.

Carbonizing processes as at present commonly performed in verticalretorts or the like in which the coal is progressively fed downwardthrough the retorts have not proven suitable for carbonizing thin layersof fuel, due to the mechanical difiiculties, both in moving such thinlayers of material through the carbonizing chambers of such retorts andin discharging the coked product. The material tends to form a plasticsticky mass at an intermediate stage of the carbonization and to adhereto the walls of the coking chamber.

Accordingly, it has heretofore been standard practice to carbonizearelative thick column of fuel; and this is essentially true where thedistillation apparatus has been directly associated with an apparatusfor the complete gasification of the carbonized fuel. It is preferablethat the fuel be fully carbonized before being moved onto the generatorfuel bed. Because however of thevery slow rates at which thick layers ofsolid fuel can be heat-treated to yield a properly carbonized product,it has been necessary in the past either to undertreat the fuel so thatit was not complete ly carbonized, or alternatively to seriously reducethe carbonizing capacity of the installation by prolonging thecarbonizing time of the charge.

of cycles, the preferred modifications of Among the principal objects ofthe present invention are to provide in an improved manner for the rapiduniform carbonization of ,a column of fuel; to provide for the uniformcarbonization of such a column of fuel by indirect application of heatfroma heating fluid flowing lengthwise of the column; toprovide in animproved manner for regulating the temperature along a column of fuelarranged in a thin layer and heated indirectly while held in place; toprovide for the carbonization of coal in thin annular layers on watergas and/ or producer cycle. These and other important objects will beclearly indicated in the course of the following description, and in theappended claims.

Broadly considered the present invention involves the carbonization of asolid fuel such as bituminous coal or lignite in elongated retorts ofannular cross section, a plurality of which are suspended in avertically-disposed, heat-insulated gas generator directly above thefuel bed of the latter. water gas generator or a producer gas generatorlThe carbonization of the fuel is effected with the annular spaceconfined between the concentric inner and outer walls of each of thesaid annular retorts. Heat for the carbonization is transmitted to thesaid walls of each retort, in part by radiation from the incandescentfuel bed and in part by means of the sensible and potential heat in thegaseous products passing in contact with the said walls of the annularretorts, as will be more specifically described hereinafter. p

The rate of carbonization of the fuel has been greatly acceleratedaccording to the present invention by exposing a relative thin annularcoluinn of the fuel to carbonizing heat applied preferablysimultaneously to two opposite sides thereof. In practice the thicknessof the fuel column annulus is less than 5" and is preferably about 3".

As rapidly as the annular column of fuel is carbonized, the resultantcoke is discharged directly onto the fuel bed of the-gas generator bysuitable means. The coke is then gasified in the said The gas generatormay be either a generator onstandard water gas cycle or producer gascycle, or upon a slightly modified series which are hereinafter setforth.

To offset or neutralize the effect of the uneven vertical distributionof heat along the respective comprises afurther stage of indirectlyheating the annular column of fuel being carbonized by means of highlysuperheated steam passed in downrun contact with either the inner or theouter walls of each retort, but preferably with both of them, the saidsuperheated steam transferring functions both as a carbonizing' agencyand as a means for equalizing the retort wall temperatures at therespective end portions thereof. This tends to preserve the'life of theretorts. Preferably potential heat recovered from the waste blast gasesfrom an earlier cycle is employed for superheating the steam employed inthe lastnamed or downrunsteam cycle.

Undesirable variations in temperature between the lower and upper endsof the carbonizing retorts also can be prevented in large part by thesuccessive addition of secondary air around the outer walls of theretorts at suitable points spaced vertically of the retorts. JThe'amounts of such air preferably are socontrolled as to effect thecombustion of predetermined proportions of the gases issuing from the.fuel bed at different elevations lengthwise of the. generator housing.-This further increases the temperature of the .-,5" hot gases contactingwith the retort walls and particularly those portions of the latterwhich are more remote from the generator fuel bed.

To further facilitate the uniform carbonization of thefuel where thesaid vertical temperature gradient exists, the outer of the concentricwalls of each retort may be slightly tapered outwardly in a downwarddirection so that the thickness of the coal layer in the lower portionof the annular carbonizing zone, which is subjected to relatively highertemperatures than the fuel in the upper portion thereof is thicker inannular cross-section than the latter. The relative thickness of thefuel layer at the respective upper and lower portions of the fuel columnis preferably lid adjusted in accordance with the above-mentionedrelationship between the thickness of the fuel layer and the timerequired for its carbonization. To further facilitate the rapidcarbonization I of the annular fuel column, the inner retort wall isadapted to be filled with refractory materials such as checker brick,Raschig rings, or the like which act to absorb heat from the hot gasespassing along in contact with the inner wall of the retort, and totransfer such heat to the layer '-='of fuel being carbonized. Thisrefractory material is very efficient as a heat-absorbing and transfermeans when employedin the manner indicated, as shown by the fact thatthe portion I of the carbonization effected. by transfer of heat fromthe inside surface of the annular fuel layer when the refractory fillingmaterial is not employed, amounts to less than. one-half of the portionof the carbonization effected by heat transferred through the inner wallof the annular retort when the inner retort member is packed with thisrefractory material.

In carrying out the process, the available heat in the hot gasesemployed in heating the respective inner and outer walls of the retortsis preferably balanced in accordance with the total larger scale,showing the upper end of the generator housing andcertain of the partsassociated therewith, portions thereof being cut away, and otherportions being shown in section;

Fig. 3 is a horizontal section of the apparatus taken along the line 3-3of Fig. 2 looking in the direction of the arrows; 1

Fig. 4 is a chart which indicates the relationshipbetween thecarbonizing capacity of the retort and the thickness of the layer offuel being carbonizedwithin the scope of the present invention, atvarious indicated temperatures within-the preferred carbonization range;and

Fig. 5 is a chart that indicates the relationship existing'betwee'n thecarbonizing capacity of a retort and the temperature at which thecarbonization is carried out,for definite thicknesses of fuel layers.

In thedrawings l0 designates a vertically arranged, gas generatingapparatus suitably lined with refractory material throughout andprovided with a cylindrical side wall 11, a base or bottom member 12,and a closed top 14. The side wall 11 is suitably constricted at anintermediate pcrtion thereof to form a lower portion 15 of reduced crosssection. A grate 17 of usual construction is positioned in the bottom ofthe generator 10 above the. base 12, the generator also being providedwith-the usual stoke holes 19-19 in its'side walls adjacent the grate.Any type of grate, as for example, a non-clinkering grate, may besubstituted for that shown.

For introducing air under pressure into the lower portion of thegenerator casing, a pipe 21 controlled by valve 23 extends through theside of the generator below the grate 1'7 and is con nected with asuitable. source of air under pres sure.

Supported from the top member 14 of the gas generator and disposed incircular arrangement at uniformly-spaced intervals are a plurality ofdepending elongated hollow tubular retort members 29 of steel or othersuitable heat-resistant metal or metal alloy such as hybnickel. Thedepending tubular members 29 preferably taper outwardly in a downwarddirection, and have their enlarged lower ends positioned near butsomewhat above the constricted portion in the generator casing.-

In a typical installation, there is approximately a 1" difference incrosssectional diameter of. the said member for each 8 feet of thelength thereof.

The upper end of each of the retort members 29 extends throughthegenerator top 14 and to a point substantially thereabove, and each isprovided with a flanged cover plate 31 having a therein, and having asecond aperture 35 located therein near the peripheral margin of thecover downward within the retort member 29 to a point adjacent the lowersurface of the generator top relatively large, centrally-disposedaperture 33 14, so as todefine anannul'ar space between the passagewayleading from the interior of the re-.

tort to the said aperture. Other radial members 40, 40 divide theremainder of the annular space between the curtain 37 and the retort29into a plurality of parts.

Each of the tubular retort mehbers 29 has disposed therein andconcentric therewith a gen erally cylindrical hollow inner retort member41 having the ends extending beyond the ends of the member 29. Each ofthe inner retort members 41 is made of suitable resistant metal or alloysuch as hybnickel, and is adapted for limited vertical movementlongitudinally of the concentric 1118111- ber 29.

. The lower margin of each of the members 41' is flared or bevelledoutwardly and extends laterally beyond the bottom margin of theconcentric retort member 29,-the arrangement being such that upon movingthe inner member 41 vertically upward the said flared lower end of thelatter engages the, bottom margin of the member 29 and forms asubstantially gas-tight seal for the bottom of the annular chamberdefined between the pair of concentric retort members 29, 41. Theconstruction of the concentric retorts 29, 41 is preferably such thatthe annular fuelreceiving space defined therebetween is less than 5" ineffective annular width, and the preferred optimum'width of this annularspace is approximately 3".

Each of the retort members 41 is substantially constricted adjacent theupper end of the retort member 29 to form an upper-end portion 45 ofgreatly reduced cross section- The said portion 45 extends verticallyupward through the aperture 33 in the cover plate '31, and its extremeupper end is closed by acap 46. The upper portion of each member 41: isoperatively secured to a housing member 47-.o'f acushioning or shockabsorbing device, a second member 49 of the said device being adjustablysecuredto the piston 51 of a hydraulic cylinder 53 which is utilized forAn elongated slot or opening 59 is provided in the upperconstflctedportion of each of the inner retorts 41 at a point above the top plate31.

, A hollow T-shaped casting 61 surrounds the portion of the member 41having the said slot 59 therein, and provides an annular chamber adaptedto be in free communication with the interior of the member 41 only whenthelatter is in its uppermost position. The interior of themember 41 isadapted to be, in communication with the upper end of'the annular fuelspace when the former is in its lowermost position. A stuillng boxassociated-with eachtop plate 31 furnishes a gas-tight seal between theinterior of casting 61 and the annular fuel space and comprises ahousing 68 in which is mounted a metal collar or seal ring 69 providedwith a plurality of grooves in its inner peripheral surface, eachadapted to accommodate a contracting piston ring 71 for cooperation withthe adjacent surface of the inretort member 41. A set screw or the like3 cooperates with the housing 68 to prevent movement of the collar 69with respect to the inner retort member. a

The upper end of the T-shaped casting 61 has an opening therein throughwhich the constricted upper end portion 45 of the inner retort member isadapted to extend. A stuffing box 75 hopper 91 is centrally mounted uponthe super-' The hopper 91 is provided with a gas-tight closure member93andis divided into structure 55.

three superposed compartments 95, 97, 99, by a pair 01"vertically-spaced funnel shaped partitions 161, 103, each open at thelower end. Leading from a conical mid-portion of the bottom of thehopper 91'are a plurality of feed lines 167, 107 adapted to convey fuelto each of the annular spaces between the inner and outer retort members29, 41. Each of the fuel feed lines 107, 107 hasa suitable gas tightvalve 109, 109- therein-and the lower end of each line 107 is branchedadjacent the generator top to form fuel feed pipes 111, 111, which openinto the upper end or one of the annular retort spaces through vopenings in opposite'sides of "the cover plate 31 between the metalcurtain 37 and the outer retort wall 29. For conveying fuel from thestorage compartment 95 into the compartment 97 at a uniform rate, apositive f ed mechanism is provided comprising a screw conveyor 113mounted upon the upper portion of member 101 and driven from a suitablesource of powerthrough pulley 115 and belt 117. The funnel shaped member103 has a central opening located directly above the midportion of thebottom of the hopper 91.

The upper closurernember 93 of the hopperis controlled by a hydrauliccylinder 127 functioning in the manner shown, through a bell crank 129.V 7 l v The'upper portion of the generator casing 10 is connected bymeans of the passageway 131 with the-upper portion of a regenerator 133of well known type provided with checker-work 135 A of a heat refractorymaterial, the said passageway 131'being provided with acut-oii valve132. The lower end of the said regenerator is connected'with a Wasteheat boiler or economizer 137 by means of a passageway 139 havingtherein a shutoff valve 145. The gas outlet end of the economizercornmunicates'with a stack 141 provided-with a hydraulically-operateddraft regu lator or closure 143.. The lower end of the regenerator isalso directly connectedwith the stack 141 by means of a pipe 147 havingvalve 149 desired.

The upper end of the regenerator 133 is contherein, for by--passingtheeconomizer 137 when I a lean gas tuye're'155. Oneend of the latter ispoint between .the said casing and the valve 23.

The other end of the ,tuyere 159 is connected with the pipe;155 at a.point therein between the valve 157 and the lean gas coolers. A branchpipe 161 controlled by valve 163 connects the stack 141, with the pipe159.

For introducing steaminto'the. apparatus, a pipe 167 controlled by valve173 has one, end thereof connected to a suitable-source of steam underpressure,the other end of the pipe 167 opening into the lower end of theregenerator 133. A branch line 169 controlled by valve 175 connects thesteampipe 167 with that portion of pipe 21 between the generator 10 andthe valve 23. V

For distributing secondary air into the genera-' tor casingimmediatelyabove the fuel bed and at vertically-spaced points .in the generatorcasing adjacent the annular retorts ,29, -and also for conducting. airfor combustion to the upper end of the regenerator 133,1--a branchconduit 177 controlled by valve 179 leads from the air pipe 21 into theupper end of the said regenerator. An intermediate point in the line 177is connected by pipe 131 with a vertically-disposed manifold 183. Thelatter is connected respectively by valve-controlled pipes 135, 187,189, with each of a plurality of vertically-spaced bustle-pipes 197,199, 291, surrounding the generator casing. Each of the saidbustle-pipes has leading therefrom a plurality of radially-disposedvalve pipes 203 provided with suitable air injecting nozzles 205extending throughthe generator wall, the arrangement preferably beingsuch that the lower set of nozzles extends through the constricted lowerportion of the generator casing immediately above the fuel bedtherein,-an intermediate set of nozzles extendsinto the casing 10 atapproximately the same elevation as the lower ends of the retort 29, andanother set of nozzles extends through 1 the casing at approximately thesame elevation as the mid-portion of the retorts 2 9.

For removing the gases and vapors as they are formed in the annularcarbonizing space between v the respective pairs of retort nlembers, 29,41,

during the carbonization of the fuel therein, each cover plate 31 hasmounted thereon a'header or casting 267, connecting the said annularfuel space through a valve pipe 209 with a bustle-pipe 211; The latteris connected by pipe 213 with a set of primary rich-gas coolers andscrubbers and therethrough with a rich gas-holder (not shown);

A pipe 215 extends into the header 207 for use in injecting Water intothe vapors flowing thereev through for. condensing tar, and the likepresent in such vapors. A steam pipe 217 extends into each of the fuelfeed lines 137 immediately below the valve 199 therein;.and a steam pipe219' extends into the upper portionof the space confined between each ofthe'tubular curtains 37 and each retort member29. Steam is preferablyintroducedinto the carbonizati'on zone through the steam lines 217 and219 for the purpose of preventing the distillation. gases from risinginto the feed lines 107 and into the curtain 37 where tar andthe likemightbe condensed and deposited. I

For carburetting the blue gas made in one of the cycles of the processaccording to one modification a pipe 221 leadingto a source of liquidhydrocarbon or other fluid carburetting medium has anend thereof openinginto the. upper portion of the regenerator 133, the said pipe beingpreferably provided with a spraying or atomizing nozzle or the like 223.

While the invention is susceptible of wide modification, depending onwhether it is desired to produce coal gas, blue gas, a mixture of coalgas and water gas or a carburetted water gas,the

following example is given solely to illustrate a. preferred applicationof the process in'the production of amodified blue gas. Assuming thatthe generator is provided with an already ignited fuel bed of coke orthe like as produced in accordance with the present invention, a chargeof fuel to be carbonized filling the annular space between'the inner andthe outer retort members of eachpair thereof, a blast of air isintroduced through pipe 31 below the grate 17 and is passed through theburning fuel'in the base of thegenerator, the said air being mixed ifdesired with a relatively small amount of steam for temperature controlpurposes. The air blast is preferably continued for approximately twominutes,

the fuel in the fuel bed becoming-incandescent, and producer gas-beingformed; The resultant products of primary blast normally issue'from theupper surface of the fuel bed at about 1600 F.

Secondary air is also admitted to the generator just above the fuel bedduring this period of the blast for the purpose of burning a part of thegases as they leave the fuel bed to assist in raising the temperature ofthe said gases to approximately 1900 this being the preferredtemperature for the 'gasesxemployed in heating the refractory materialpositioned within the inner one of each pair of concentric retortmembers.

The productsof the primary air blast are then The resultant products ofcombustion of this portion of the lean gas are conducted. downwardlythrough the regenerator and from there they maybe led through the wasteheat boiler and through the stack to the, atmosphere. The balanceof, thelean gas'fiowing'in pipe 155 is conducted through valve' 157; through alean gas cooler to a lean gas holder onto a common mixing holder.

Another portion of the gases leaving the generator fuel bed passupwardlyaroundthe outer] retort'rnember 29, giving up their heat throughthe said retort walls to the fuel being carbonized.

Thesecooled gases after such heat exchange flow with the blast gasesentering the latter from the lean gas line 155 and may be burned withthe latter for the purpose of heating-the checker work in theregenerator 133. the hot blast gases from the generator throughpassageway 131 into I the upper part of the regenerator where they mixpass upwardly in the gas generator, predetermined amounts ofair areintroduced into and mixed therewith at a plurality of points spacedvertically of the generator, for the purpose of maintaining the variousportions of the outer retort walls at the desired temperature and foruniformly carboniaing the fuel. At this point in the process the airblast'is discontinued, valves 23, 191, 193, 195, 143 and 1'79being'closed, and the uprun make cycle is begun. Steam is admitted intothe lower part ofthe gen erator beneath the grate by opening valve 175in the steam line 169, steam valve 173 being closed. The blue gas formedby the steam in passing upward through the incandescent fuel bed isagain divided, as in the previous or air blast cycle, a predeterminedpart of the hot flue gas being conducted along each refractory-filledinner retort member to assist in supplying heat thereto for thecarbonization of the annular layer of material. This part of the bluegas thereafter passes through the ports 59 in the upper end of the innerretort members and through the lean gas bustle pipe and tuyere 155 tothe primary lean gas coolers and thence to storage. It may be stored ina separate holder from the producer gas previously conducted through thepipe 155, or it may be mixedwith the portion of the primary blast gasesthat were taken to storage during the first cycle of the operation. Asecond predetermined por tion of the blue gas generated in the second oruprun make cycle passes upward through the generator in contact with theexternal retort walls and is thereafter conducted from thegeneratorthrough the passage 131 and the pipe 151 to the tuyere 155where it mixes with the blue gas passing upwardly through the innerretort member and is conducted therewith through the lean gas coolers tostorage.

During this uprun make cycle the fuel bed is rapidly cooled and theproportion of the heat radiated to the retort members from theincandescent fuel bed falls off appreciably. In order to maintain asatisfactorily uniform coking temperature vertically along the fuelcolumn during this cycle, sufficient air preferably is intro,- ducedthrough the pipes 203 to burn predetermined portions of the said bluegas so as to maintain the hot contacting with the inner and outer wailsof the annular fuel column at the detemperature during such contact. theuprun cycle has been in operation for the desired length of time, it isterminated by closing the steam valve 1'75, the various valves .191,193, 195 in the air line, and valve 157.

A downrun cycle is now started during which is admitted through line 167into the lower n of the regenerator, the valves 145 and 149 elyconnecting the bottom of the regenwaste heat boiler and with the closed,and the valve 165 in conduit 159 being opened. The steam is drawnupwardly through the regenerator, at the same time being highlysuperheated by heat transferred thereto from the highly heated checkerwork. The thus steam is thereafter divided if and as M d into twoportions. One of the said portio...s passes through the passageway 131into the upper part of the generator casing, and descends Aftergenerator fuel bed in a manner to offset the heating of the lowerportions of the-respective retort members to higher temperatures thanthe upper portions thereof by the heat radiated from the fuel bed and bythe sensible and potential heat of the gases formed in the two previouscycles. The remaining portion of the superheated steam passing upwardlythrough the regenerator, is conducted through the pipes 151 and 155, thejunction box 65 and the slots 59, and into the inner one of each of thepairs of concentric retort members. The said superheated steam thenflows downwardly through the said members, giving up its sensible heatto the refractory fillings thereof, and it thereafter passes through thehot fuel bed 220. The blue gas thus formed by thereaction of this steamwith the highly heated fuel is conducted through conduit 159 to theprimary lean gas coolers and thence to storage. f

The down run cycle preferably lasts for about one minute and a quarter,after which a short uprun of purge steam is effected preparatory toagain starting the air blast of another cycle. The

purge steam and gases carried thereby are preferably conducted either tolean gas holders or exhausted to atmosphere.

The distillation products obtained during the carbonization of the fuelcontaining for example various liquefiable and gaseous hydrocarbons,coal gas, tar, water vapor, ammonia and the like, are withdrawncontinuously from the upper part of the annular fuel space during eachof the above mentioned cycles and pass through header 207, bustle pipe211, and the pipe 213 to a set of primary rich gas coolers preferablyunder subatmospheric pressure, and thence to a rich gas holder or acommonstorage holder.

These gas-making cycles are continuously repeated in the order givenuntil the carbonization of the fuel in at least one of the retorts hasbeen,

completed. Thereupon the inner retort member 11 is moved downward byoperating the hydraulic cylinder controlling it, and the carbonizedmaterial is discharged by gravity downwardly onto the generator fuelbed. The flared portion of the bottom margin of the inner retort memberfunctions as a support for the fuel 'column when it is in its upmostposition, and .it I

also acts as a valve to prevent substantial pro portions of the heatinggases such as producer gas and the like from passing to the fuel columnand escaping into the rich gas offtake during the carbonization period.When the inner retort member is in its lowered position, the flaredbot-'tom thereof assists in breaking up large lumps of coke falling 'upon itduring the dischargin'g process.

The retort pairs are preferably filled in succesgenerator is drawn intothe fuel bed 220 and does not interfere with the process.

Lean producer gas and the like are prevented from flowing through thespace lying between the two concentric retort members during the imethat the inner member is lowered for discharge of coke, due to the factthat the slot 59 thenis positioned below the seal ring 69. During thistime valve 209 is closed to prevent the stage by. stopping the conveyor113.

passage of lean gas into the rich gas bustle-pipe 211. When the innerretort member is again raised to its former position with its flaredlower margin in sealing contact with the lower margin of the outerretort member, the slot 59 again permits communication between theinside of the inner retort 41 and the junction box 65, and concurrentlybreaks communication between the latter and the annular fuel space; Thesaid annular fuel space is thereupon again charged with fresh'fuel fromthe fuel hopper by the operaing pipes 107 into the retort offsets anytendency for distillation gases to collect in these pipes. The currentof stream introduced into the upper portion of each retort between theinner retort member 41 and the metal curtain 37 prevents theaccumulation in the space of distillation gases which might deposittherein objectionable materials such as tar.

According to a modification of the process in which a carburettedcombustiblegas is produced,

the uprun make cycle is so controlled that the gaspassing upward throughthe generator is at least in large part conducted into the regeneratorby properly setting or closing the valves 157 and 158, and'opening thevalvesl53 and 154i,

the said gases then being conducted downward through the highly heatedcheckerwork in the regeneratoni Simultaneously a spray of suitablecarbureting fluid'such as a hydrocarbon oil or the like is introducedinto the upper portion of the regenerator and if necessary is vaporizedand fixed at the temperature existing therein. The enriched blue gas isconducted from the lower end of the regenerator direct to the pipe 141and, through branch pipes 161 and 159, to suitable gas coolers andscrubbers and then to storage,--the stack valve 143 being closed. Theeconomizer is preferably bypassed to avoid the possibility oftar and thelike condensing-in the flues thereof.

In like manner the last portion of the hot producer gases formed in thegenerator during the blast cycle may be carburetted'by spraying aca'rburetting fluid into that portion thereof which is passed downwardthrough the highly heated checkerwork in the regenerator. Theintroduction of air to the regenerator through the air pipe 1'77 ispreferably discontinued prior to the introduction of the carburettingfluid into the said gases. 7

Instead of conducting all of the gases formed in the generator 10 duringthe uprun make cycle through the regenerator, which herefacts as acarburetor, a portion or an of the gases passing throughthe inner retortmembers of each pair may be conducted direct to lean gascoolers and tostorage with or without portions of the gases leaving the generatorthrough the passageway .31, by suitable adjustment of the check valves154 and 158.

approximately no additional cost.

Although both the inner and the outer retort members of each concentricpair are preferably fabricated from the same kind of heat resistantmetal, it is within the scope of the present invention to make the innerretorts of different metal or alloy than that of which the outer retortsare made, so that they will exhibit different physical characteristicsunder the conditions of use. In order therefore to compensate for anyunbalanced elongation of the inner retort members under the effect oftheirown weight at the high temperatures employed, and to properlymaintain a substantially gastight seal between the lower ends of theinner and outer retorts, the extreme-upper end of the inner retort maybe threaded externally for cooperation with threads formed upon theinterior of, the lower end of the housing member 47. Other similar meansfor accomplishing the same result may be employed if desired. Forexample, the flared bottom of the inner retort of each pair may beseparable from the tubular portion of such inner retort and may beadapted for adjustment longitudinally thereof.

The compression springs 57 and 58 permit the raising and lowering of theinner retort member without undue jarring and injury to the apparatus. 1

It will be obvious thatother methods of charging coal into theretort maybe substituted for that specifically shown and described. It is alsowithin the spirit of the present invention to make the outer retortmember cylindrical while employing a reverse taper on the inner retortmember so that the sides of the latter slope inwardly in a downwarddirection, or if preferred both inner and outer retort members may beslightly tapered.

By employing a cylindrical inner retort member, and providing the outerretort with an outward and downward taper, it is possible'to vary thethickness of the annular fuel layer to compensate for the usual verticaltemperature gradient along the retort walls, especially in instanceswhere the said gradient has not been substantially eliminated by thecombustion of effective amounts of secondary air as already described.In this way it is possible to appreciably increase the carbonizationcapacity of retort-s of the type here shown and described at Therelative proportion of the carbonizing heat distributed along therespective surface of the inner retort and the onterretort wall may becontrolled by suitable vacuum-producing means arranged in the lean gas'offtake line from either of the said retort members or by pressurecontrol flow involving the use of regulating valves hereinbeforementioned.

An apparatus construction in which a group of four uniformly spacedcarbonizing retorts is supported in the upper part of a gas generatorhousing has proven to be very efiicient and gives a very highcarbonizing capacity per unit of time per square foot of metal heatingsurface employed. The process is preferably carried out .with effectiveretort temperatures of from 105 v to 1500 F. At temperatures much inexcess of 1500 F., while the rate of carbonization is accelerated, thereis a tendency toward cracking of the tar vapors, which interferes withthe production of primary tar and reduces the tar residue credit, bothfrom the point of yield and quality. On the other hand at temperaturessubstantially below 1050 F., the carbonizing capacity of the assembly ismaterially reduced, when using the above-mentioned preferred thicknessof coal or athicker layer thereof, until a point is reached at which thenumber of .retorts required in order to permit the continuous operationof the generator introduces many structural difficulties.

It is within the purview of the present invention to utilize forcarbonizing the fuel both the luminous and the nonluminous or obscureradiations from the incandescent generator fuel bed; and the area ofthat portion of the tubular retort surface which is exposed directly tosuch radiated heat is preferably the maximum which is consistent withthe maintenance of a suitably thin fuel layer in the carbonizing zone.

Fig. 4 clearly illustrates the rapidly increasing rate at which fuel iscarbonized when exposed to heat in the low temperature carbonizationrange, in layers 5" in thickness or less. The particular valves fortemperatures of 1050 F. to 1400 F. and 1500 F. are shown. Ordinarily incarbonizing fuel in annular layers over a water gas generator, certaindifliculties are encountered where fuel layers of over 5 in thicknessare employed, due to the excessive retort space required to carbonizethe necessary amount of fuel to serve the generator fuel bed, and to theresultant excessive cost of the apparatus assembly.

Fig. 5 illustrates the effect upon the carbonization capacity of aretort assembly due to varying the carbonizing temperatures employed.This effect is separately indicated for fuel layers respectively 3 and5" in mean thickness, between temperatures of 1050 F. and 1800 F.However, at temperatures below 1050" F. the carbonization capacity ofthe retorts, when using the optimum thickness of coal layer, 3", isreduced to a point Where thenumber of retorts required in aself-contained gas generator set is excessive and imposes objectionablestructural limitations.

Among the important features of the present invention is the flexibilityof control which it permits of the B. t u. value of the gases formed bythe gasification. of' fuel. In addition to the coal gas produced by thefuel distillation the gases produced in the generator in each cycle ofthe process may be collected separately or the said gases or anydesired'portions thereof may be mixed to give a gas of the desired B. t.u. value. Moreover the heating value of these gases can be increased asdesired by carburetting selected portions of the gases passing from thegenerator as previously described. Predetermined portions of the gasesare preferably burned in the upper portion of the generator and in theregenerator, and the resultant products of combustion, or part thereof,may be mixed with;

the unburned portions of the gases and carried to storage.

I claim: 1. Apparatus for concurrently carbonizing and gasifying solidfuel which comprises a vertically disposed generator housing, air andsteam lines leading into the lower portion thereof, a plurality of pairsof concentric hollow tubular members mounted in the upper part of thegenerator housing and forming a plurality of carbonizing retorts ofrelatively thin annular cross section, a removable bottom closure foreach of the said annular retorts, .a' regenerat'or, means for connectingthe inner member of each pair of retorts with the regenerator, means forconnecting the upper portion of the generator housing with theregenerator, and means forcontrolling the relative amounts of heatinggases passing into the regenerator respectively through the inner retortmembers and through. the generator housing.

2. Apparatus for the concurrent production of combustible gas and acarbonized solid fuel which comprises a vertically-disposed generatorhousing having a grate, air and steam lines leading to the said housingbelow the grate, a plurality of pairs of spaced-apart, concentricallyarranged tubular members mounted in the upper portion of the housing,each pair of members de fining between them an annular space, "neans forlongitudinally moving one of the said tubular members of each pair,means associated with the last-named or movable member and cooperatingwith the other of the said tubular members to form a bottom closure forthe said annular space when the movable tubular member is in itsuppermost position, the concentric members being spaced closer togetherat their upper portions than at their lower portions, means for in-'troducing fuel to be carbonized into the annular space between each ofthe pairs of concentric retorts, and a plurality of conduits forseparately conducting hot combustible gases along within the inner ofthe concentric members and along the on er surface of the outer of theconcentric members and for conducting the said gases to storage.

3; Apparatus for the concurrent production of combustible gas and acarbonized solid fuelwhich comprises a vertically-disposedgeneratorhousing having a grate, air and steam lines leading to the saidhousing below the grate, a plurality of pairs of spaced-apart,concentrically-arranged tubular members mounted in the upper portion ofthe housing, each pair of members defining between them an annularspace, a removable bottom closure for the said annular space, means forlongitudinally moving one of the said tubu lar members of each'pair, andyielding means rality of pairs of. spaced apart, concentricallyarrangedtubular members mounted in the upperportion of the housing,.:each pairofmembers defining between them an annular space,

actuating means for longitudinally moving one of thesaid tubular membersof eachpair, means associated with the last-named or movable member andcooperating with the other of the said tubular'members to forma bottomclosure-for the said annular spacewhen movable tubular member is in itsuppermost'position, and adjustable means associated with the saidmovable tubular member for moving the latter 1ongitudinally of the saidactuating means for in- .suring a substantially gas-tight seal betweenthe lower portions of the two concentric niernbers when the movable isin its upper-' comprises a vertically disposed generator hous-' ing, airand steam connections leading thereto, a plurality of pairs ofconcentric tubular members mounted in the upper part of the generatorhousing and forming a plurality of carbonizing retorts of relativelythin annular cross section, the bottom margin of one of each pair of theconcentric members being flared to form a bottom closure for the annularchamber defined by the said pair of concentric members, means for movingone of the concentric tubular members of each pair longitudinally of theother, and a plurality of vertically-spaced groups of fluid inlet pipesopening into the generator housing,

at least some of the said groups being disposed adjacent the tubularmembers.

7. Apparatus for the concurrent carbonization and gasification of solidfuel which comprises a vertically-disposed generator housing, air andsteam connections leading thereto, a plurality of pairs of concentric,hollow tubular members:

mounted in the upper part of the said generator housing and defining aplurality of carbonizing retorts of annular cross section, one of thetubular members of each pair having its lower margin fiaredto'form abottom closure for the annular retort defined by the respective tubularmembers of that pair, means, for vertically moving one of the tubularmembers of each pair to selectively bring the flared bottom margin ofone tubular member into contact with the bottom edge of theconcentrically disposed tubular member so as to form abottom closure forthe'car bonizing retort or to move the flared bottom out 7 of suchcontact to permit discharge of carbonized fuel from the retort into thelower part of the said housing, a regenerator and automatic meansassociated with the inner one of each pair of tubular. members forestablishing communication between the interior of the said inner memberand selectively with a lean gas holder or with the regenerator only whenthe'said flared bottom margin of one of the said members is inraisedposition in contact with the bottom edge of the other member of suchpair.

8. The apparatus as defined in claim 7 includ-, ing means dividingtheinner one of the concentric tubular members of each pair into aplurality of superposed compartments, each of said compartments beingprovided with refractory filling-bodies.

,9. Apparatus for concurrently carbonizing and gasifying solid fuel,comprising a vertically-di posed generator having a grate therein, airand steam lines leading to the generator below the grate, a pair ofconcentric hollow tubular mem: bers mounted in the upper part of thegenerator and forming the respective side walls of a carbonizing retortof relatively thin annular cross section, means for longitudinallymoving one of the said tubular members, a bottom closure for the retortsecured to one of the tubular members and adapted to close the retortatrthe bottom only when the said-movable member is in its up-'permostposition, and means adapted when the said movable tubular memberis in its uppermost position to directly connect the space within theinner tubular member of each pair selectively with a regenerator andwith-lean gas storage.

10. Apparatus for concurrently carbonizing and 'gasifying solid fuel,comprising a verticallydisposed generator having therein a grate, air

and steam lines leading to the generator below the grate, a pair ofconcentric-hollow tubular members mounted in the upper part of thegen-.erator and forming the respective side walls of a carbonizing retort ofrelatively thin annular cross section, an adjustable bottom closure forthe retort spaced above the grate, fluid inlet means in the upper partof the annular retort adapted to prevent accumulations of tar and thelike within the upper end of the retort, and means for introducing solidfuel into the retort and for uniformly distributing such fuel therein.

11. Apparatus for concurrently carbonizing and gasifying solid fuel,comprising a verticallydisposed gas generator having a grate therein,air

the curtain and the said inner member, an inlet for solid fuel connectedwith the retort between the said curtain and the. outer-member of sachpair of tubular members, and means connected with the upper part oftheretort for conducting rich gas therefrom.

l2. Apparatusv for concurrently carbonizing and gasifying solidfuelwhich comprises, a vertically disposed generator having a grate, airand steam lines leading-to the generator below the grate, a pair ofconcentric hollow tubular mem bers mounted in the upper part of thegenerator and forming the respective side walls of a carbonizing retortof'relatively thin annular cross-sec--- tric tubular members and adaptedto establish 1 communication between the interior of the said innermember'and theregenerator when the said tubular member is in itsuppermost position, a valve-controlledgas ofitake connected with thesaid annular retort, means for introducing steam into the lower portionof the regenerator, and a rich gas oiftake leading from the lowerportion of the regenerator. I

13. Apparatus for concurrently carbonizing and gasifying solid fuelwhichcomprises, a ver-' tically'disposed generator having a grate, airand steam lines leading to the generator below the grate, a pair ofconcentric hollow tubular members mounted in the upper part of thegenerator and forming the respective side walls of a carbonizing retortof relatively thin annular cross-section, means for longitudinallymoving oneof the said tubular members, a bottom closure for the retortsecured to one of the tubular members and adapted to close: the bottomof the retort when the movable member is in its uppermost position only,a regenerator, valve controlled means connecting the upper part of thegenerator housing with the regenerator, a valve-controlled conduitconnected with the upper part ol the regenerator, means associated withthe last named conduit and with the inner of the pair of concentrictubular members and adapted to establish communication between theinterior of the said inner member and the regenerator when the saidtubular member is in its uppermost position, a valve-controlled gasofftake connected with the said annular retort, means for introducing acarbureting fluid into the regenerator, means for'introducing steam intothe lower portion of the regenerator, a rich gas offtake leading fromthe lower portion of the regenerator, and means for introducingsecondary air into the i generator at vertically-spaced points above thegrate therein.

14. Apparatus for concurrently carbonizing and gasifying solid fuelwhich comprises a vertically disposed gas generator having a gratetherein, air and steam lines leading to the generator below the grate, apair of concentric hollow tubular members mounted in the upper part ofthe generator and forming the respective side walls of a carbonizingretort of relatively thin annular cross section, means forlongitudinally moving one of the said tubular members, the bottom 010-sure for the retort being secured to one of the tubular members andbeing adapted to close the bottom of the retort when the movablememberis in its uppermost position only, a regenerator, a valved-controlledconduit connecting the upper part of the generator with the regenerator,other means associated with the movable tubular member and adapted toestablish communication between theregenerator and the interior of themovable member only when the latter is in its uppermost position, avalved-controlled rich gas ofitake leading from the carbonizing retort,and a valve-controlled rich gas offtake leading from the lower portionof the regenerator.

15. Apparatus for concurrently carbonizing and gasifying solid fuelwhich comprises, a verticallydisposed generator having a grate, air andsteam lines leading to the generator below the grate, a pair ofconcentric hollow tubular members mounted in the upper part of thegenerator and forming the respective side walls of a carbonizing retortof thin annular cross-section, means for longitudinally moving one ofthe said tubular members, a bottom closure for the retort carried by oneof the tubular members and adapted to close the bottom of the retortonly when the movable member is in its uppermost position, aregenerator, valve-controlled means connecting the upper part of thegenerator with the regenerator, a valve-controlled conduit establishingcontrolled communication between the interior of the said movable memberand the regenerator when the said member is in its uppermost position, avalve-controlled gas offtake connected with the said annular retort,means for introducing a carbureting fluid into the regenerator,

means for introducing steam into the lower portion of the regenerator,rich gas ofitakes respectively leading fromlthe lower portion of theator, valve-controlled means connecting the u'pregenerator and from thebase of the generator, and means for controlledly introducing secondaryair into the generator at vertically-spaced points tubular members, abottom closure for the retort carried by one or the tubular members andadapted to close the bottom of the retort when the movable member is inits uppermost position only,

a regenerator, valve-controlled means connecting the upper part of thegenerator directly with the regenerator, means cooperatively associatedwith thesaid movable memberand adapted to establish regulatedcommunication between the regenerator and the interior of the movablememher only when the latter is in its uppermost position, avalve-controlled rich gas offtake leading from the carbonizing retort, avalve-controlled gas off-take leading from the lower part of theregenerator, means for introducing secondary air into the generator atvertically-spaced points above the grate therein, and means for introducing secondary air into the upper part of the. regenerator.

17. Apparatus for concurrently carbonizing and gasifying solid fuel,which comprises a vertically-disposed gas generator having a gratetherein, air and steam lines leading to the generator below the grate, aplurality of spaced pairs of concentric hollow tubular members mountedin the upper part of the generator, the

ing the respective side walls of a carbonizing retort of thin annularcross-section, means for independently longitudinally moving one of thesaid tubular members of each pair, a bottom closure for each retortcontrolled by one of the tubular members forming the same independentlyof the other retorts adapted to close the bottom of such retort when thesaid movable member is in its uppermost position only, a regenerper partof the generator with the regenerator, means cooperating with themovable tubular member of each pair thereof and adapted to establishcontrolled communication between the regenerator and the interior of thesaid movable member only when the latter is in its uppermost position,valve-controlled rich gas offtakes leading from each carbonizing retort,and a valvecontrolled rich gas oiftake leading from'the lower part ofthe regenerator. V e

18. Apparatus for concurrently carbonizing and gasifying solid fuel;which comprises a verticallydisposed gas generator having a gratetherein, air and steam lines leading to the generator below the grate, aplurality of spaced pairs of concentric hollow tubular members mountedin the upper part of the generator, the

tubular members of each of the said pairs forming the respective sidewalls of a carbonizing retort of thin annular cross-section, means forindependently longitudinally moving one ofithe said tubular members ofeach pair, a bottom closure for each retort controlled byone of thetubular members of each of the said pairs formtubular members formingthesame independently of the other retorts and adapted to close the" bottomof such retort when the said'movable member is in its uppermost positiononly,.a regenerator, valve-controlled means connecting the upper part ofthe generator with the regenerator, means cooperating with the movabletubular member of each pair thereof and adapted to conduct regulatedportions of hot gases from the interior of the said movable memberselectively to the regenerator and to a source of lean gas storage onlywhen the said movable member is in its uppermost position, a valvecontrolled rich gas offtake leading from each carbonizing retort, avalve-controlled rich gas oiftake leading from the lower portion of theregenerator, means for introducing a carbureting fluid into theregenerator, and means for introducing secondary air into the generatorat vertically-spaced points above the grate therein and longitudinallyof the said retorts.

19. Apparatus for concurrently carbonizing and gasifying solid fuelwhich comprises, a vertically-disposed generator, air and steam linesleading to the lower portion thereof, a plurality of pairs of concentrichollow tubular members mounted in the upper part of the generator andforming a plurality of carbonizing retorts of thin annularcross-section, a removable bottom closure for each of the said annularretorts, a regenerator, means for separately connecting the inner memberof each pair thereof with'the regenerator, means for connecting theupper portion of the generator with the regenerator, means forcontrolling the relative proportion of hot gases passing to theregenerator respectively through each of the inner tubular members anddirectly from the generator, a gas ofitake connected with the lowerportion of the regenerator, and a plurality of controlledverticallyspaced fluid inlet pipes opening into the generator adjacentthe tubular members.

ALFRED JOHNSON.

